Pillar Upper Structure Force Transmission Path
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Solution Overview
Problem
The existing body upper structure of vehicles is prone to destruction during side impacts due to the transmission of impulsive forces, which causes the roof side rail inner member to break at the weld, leading to collapse and cross-section crumbling of the roof side rail.
Innovation Solution
A pillar upper structure that includes a roof side rail with an inner and outer member, a center pillar, a bulkhead within the space formed by the rail members, and a roof side reinforcement, where the impulsive force is directed through multiple coupling points to efficiently transmit force to the reinforcement, reducing the stress on the weld between the rail members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the roof side rail inner member and outer member are welded together at the roof side end, then the structural integrity is improved, but the weld becomes vulnerable to breaking under impulsive force during side impact
Solution Approach 1:
The bulkhead acts as an intermediary component between the roof side rail inner member and outer member. It distributes the impulsive force from the center pillar across multiple coupling points (third and fourth coupling portions) rather than concentrating it at the weld, thereby protecting the weld from direct impact loading while maintaining structural integrity
Solution Approach 2:
The force transmission path is segmented into multiple stages through the bulkhead and its coupling portions. Instead of a direct force path to the weld, the impulsive force is divided and transmitted through multiple coupling points (second, third, fourth, and fifth coupling portions), dispersing the load and preventing concentration of stress at the weld
2Object-affected harmful factors
If the roof side reinforcement is added to prevent inner member collapse, then the protection against side impact is improved, but the roof side rail inner member collapses outward causing cross-section crumbling
Solution Approach 1:
The bulkhead serves as a mediator that prevents direct transmission of impulsive force to the roof side reinforcement. By coupling the bulkhead to both the inner and outer members at multiple locations, it creates an alternative force transmission path that avoids concentrating load on the reinforcement, thereby preventing collapse and cross-section crumbling
Solution Approach 2:
The bulkhead is pre-installed within the space formed by the rail members to establish a protective structure before impact occurs. This preliminary structure is designed to absorb and distribute impulsive forces, preventing the subsequent collapse of the inner member and damage to the reinforcement during actual side impact
Data Source
AI summary
A roof side rail inner member and a roof side rail outer member of a roof side rail are coupled to each other in a first coupling portion. The roof side rail and a center pillar are coupled to each other in a second coupling portion. A bulkhead is coupled to the roof side rail outer member in a third coupling portion in a space within the roof side rail. The bulkhead is coupled to the roof side rail inner member in a fourth coupling portion. The roof side rail inner member and the roof side reinforcement are coupled to each other in a fifth coupling portion below the first coupling portion. The second, third, fourth, and fifth coupling portions together form a route along which impulsive force exerted to the center pillar is transmitted to the roof side reinforcement.